title: A new on-fluorescent probe for manganese (II) ion.
abstract: A new fluorescent probe for Mn(2+) ion, (6E)-N-((E)-1,2-diphenyl-2-(pyridin-2-ylimino)ethylidene)pyridin-2-amine (L), has been synthesized from benzil and 2-amino pyridine and characterized. In 1:1 (v/v) CH3CN:H2O (pH 4.0, universal buffer) L exhibits fluorescent intensity with emission peak at λmax 360 nm on excitation with photons of 310 nm. Fluorescent intensity of L increases distinguishingly on interaction with Mn(2+) ion compared to metal ions--Na(+), K(+), Ca(2+), Mg(2+), Ba(2+), Fe(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+), Hg(2+), Pb(2+) and Ag(+) individually or all together. The enhancement in fluorescent intensity is due to snapping of photoinduced electron transfer (PET) prevailed in free L. Fluorescence and UV/visible spectral data analysis shows that binding stoichiometry between Mn(2+) and L is 1:1 with log β ≈ 3.0. Both L and its Mn(2+) complex were optimised using density functional theory (DFT) and vibrational frequency calculations confirm that both are at local minima on the potential energy surfaces.
authors.affiliation: Department of Chemistry, Gauhati University, Guwahati, 781014, Assam, India.
authors.forename: Kaku
authors.initials: K
authors.lastname: Dutta
authors.forename: Ramesh Ch
authors.initials: RCh
authors.lastname: Deka
authors.forename: Diganta Kumar
authors.initials: DK
authors.lastname: Das
mesh_terms: D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry*; D007477:Ions / Q000032:analysis; D008345:Manganese / Q000032:analysis*; D008958:Models, Molecular; D015394:Molecular Structure; D011725:Pyridines / Q000138:chemical synthesis / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: C000591681:(6E)-N-((E)-1,2-diphenyl-2-(pyridin-2-ylimino)ethylidene)pyridin-2-amine; D005456:Fluorescent Dyes; D007477:Ions; D011725:Pyridines; D008345:Manganese